Bobbin



June 4, 1940. w. J. SIMPSON.

BOBBIN Filed Dec. 19, 1938 2 Sheets-Sheet 1 June 4, 1940.

W. J. SIMPSON BOBBIN Filed Dec. 19, 1938 2 Sheets-Sheet 2 15121672207 Mam??? (Z1523 rza'ea fll 1 Patented June 4, 1940 UNITED STATES PATENT OFFICE Bo Bm' William J. Simpson, Woburn,.Mas s. Application December 19, 1-938, Serial No. 246,679 u 3 Claims. (01. 112-251) This invention relates to an improvementina wound'bobbin and. in the method-of producing the same. The bobbinembodying this invention is of the general type comprising a tubular core of paper or similar compressible material upon which the thread is Wound, and annular shells on the core at the sides of the wound mass.

The primary object of this invention is to pro-' vide a bobbin of the general type above set forth wherein the shells or heads are firmly locked against rotation on the core or barrel and are forced against the sides of the wound mass to compress the latter axially so that the thickness thereof is materially decreased, the axial compression of the mass being greatest at the portion. adjacent the core and decreasing as the distance from the core increases.

A further object of this invention is to provide such a bobbin wherein the tubular core or barrel is expanded at its ends to engage the shells and throughout its length to provide ridges which coact with the expanded ends thereof to' lock the shells or heads in place and which act to com-' press the wound mass outwardly.

Another object of this invention resides in the method of forming thebobbin by a succession of separate stages.

These andother objects of the invention will appear from a consideration of the following description thereof and of thedrawings which form a part thereof and in which:

Figs. 1 and 2 illustrate in sideand front elevation, respectively, a mass of thread wound upon a core; I 1 Figs. 3 and 4 are similar views of an'annular Fig. 6 and of the apparatus'by which the first step of assembling is carried out;

Fig. 8 is a sectional view of a bobbin completely assembled in accordance withthis invention and portions of the apparatus by which the final step of assembling was carried out;

Fig. 9 is a sectional view of the bobbin and the apparatus shown in Fig. '7 atthebeginning of the final step of assembling; Y

.Figs. 10 to inclusive disclose on a larger scale one side of a bobbin and a [portion] of the mass and eore2| may be carried out in any various-stages in the conversion of the bobbin of Fig.- 6 into the bobbinof Fig. '7 to complete the assembly thereof; and

Fig. 16 is an-enlarged detail view of aportion 5 ofthe'completed bobbin.

The bobbin comprises a wound mass of thread 20 upon atub'ular core 2| and annular shells 22 supported on the'core 2|. The core 2| is of paper or other compressible material. The shell or 1 head 22 is of similar material and. the central opening 23 thereof is of a diameter substantially less than the outside diameter of the core.

The assembly of the shells 22 withthe wound suitable manner.. It has been found particularly "satisfactory in assembling to employ two sets of diesv as set forth in the drawings and. described 1 hereinbelow,

' The fir'st set of dies 25 each has a head engaging face 26 and a central recess or bore 21 leading from the face 26. The recess 21 is cylindrical and has-a diameter such as to receivethe 'end of the core 2|. ,-The entrance to the recessis rounded or chamfered as "shown m the, drawings. Fixed. in one of the dies 25 is a rod 28 which extends through the center of the recess 21. The diameter of the rod 28 is such as to receive and support the core 2| and shells 22 as'shown in Fig. '7.

Fig. 5' illustrates the position of the various elements prior to initiating the assembly of the bobbin. The wound mass 20 on the core 2| is between the dies 25, and the shells 22 are between the mass and core and the dies, one shell being -shown supported by the rod 28. The dies 25 shell for abobbin before such shell is-assembled are'then advanced'against the mass 20, the rod 28 entering the core 2 I, to force the shells 22 against the sides of the mass 20 (see Fig. '7). As the shells or heads 22 approach the mass, theirinner peripheries are forced over the ends of the core 2|, I thus providing outwardly directed lips 29. The mass 20is somewhat'compressed axially and the shells 22 are held in contact therewith by the frictional engagement of theflanges 29 with the core. I

'I'he bobbin, now in the condition shown in Fig. 6, is then further compressed between the second set of dies (see Figs. 8 to 15 inclusive). Eachsuch die. 30 has a shell engaging face 3| provided with anannular recess 32 of peculiar conformation. Projecting centrally from the face 3 of one die 30 is a rod 33 similar in dimen-' sion to the rod 28. In the face 3| of the other die 30 is a central bore or pocket 34-adapted to receive the end of the rod 33 after it has passed through the core 2|.

The completed bobbin shown in Fig. 8 is the result of a. plurality of successive stages that take place as the dies 30 are brought into contact with the bobbin which is initially in the condition shown in Fig. 6. These stages are illustrated in Figs. to inclusive. While these drawings show only the lower part of one side of the bobbin, it will be understood that the upper part as well as the opposite side are similarly treated.

The dies 30, when brought into contact with the ends of the core 2| (Figs. 9 and 10), first expand the end portions of the core progressively outward so as to cause the ends of the core to form flanges 35 which overlap the edges of the lip 29. It will be noted that the rod 33 within the core 2| prevents any expansion inwardly of the ends of the core so that the internal diameter of the core of the completed bobbin is substantially uniform from end to end; The thickened ends of the core thus produced have outwardly sloping or flaring peripheral surfaces, which, due to the compression and crushing of the material, are more or less irregularly ribbed or corrugated. As pointed out above, the core is of paper or other compressible material so that the axial compression of the core results in a thickening of the core ends and the formation of the flanges 35, as shown in Figs. 11 and 12.

Further compression causes the flanges or thickened ends 35 to force the edges of the lips 29 longitudinally of the core and to reverse their direction (Figs. 13'and 14) so that they slope inwardly instead of outwardly. During this action the material of the head is subjected to a radial outward stress tending to burst the head, with the result that it is placed under hoop tension. The faces 3! of the dies are finally brought into face contact with the heads and change the formation thereof, as shown in Fig. 15. The body of the core is forced by the pressure exerted to expand outwardly along its length to form exterior ridges 36 (Fig. 15) which increase the outward compression upon the wound mass 20. The heads thus forced into contact with the sides of the mass compress the entire mass, exerting the greatest pressure at the inner periphery and a decreasing pressure as the distance from the core increases.

During the final compression, the flanges 35 are further expanded outwardly so that their sloping outer surfaces are forced into very intimate contact with the inner sloping surfaces 3'! of the heads, increasing the hoop tension stress in the latter andproducing such close engagement between the parts that the heads cannot rotate on the core even when the bobbin is empty. The ribs or irregular corrugations formed by the crushing of the material of the core further assist in interlocking the core and head so as to prevent relative rotation of the parts. The outer edges of the heads preferably are bent to form flanges 38 which extend inwardly over the edges of the wound mass 20.

From the above it will be apparent that the shells 22 are forced against the sides of the wound mass to compress it axially, the compression being greatest at the inner periphery and gradually decreasing toward the outer periphery; that the ends of the core 2| are expanded and forced into surface contact with the shells 22, that the outer surface of the core 2| is provided witha plurality of ridges 36 as the result of the axial compression thereof, which ridges set up an outwardly exerted compression of the mass 20, and that the heads are subjected to hoop tension. The result thereof is that the shells are held against rotation relative to the core and wound mass, and that the wound mass is placed under compression exerted both axially and outwardly from the center thereof, thereby preventing rotation of the mass about the core and ensuring an even feed of the thread therefrom.

While one embodiment of this invention has been shown and described, it will be understood that the invention is not limited thereto and that other embodiments may be made without departing from the spirit and scope thereof as set forth in the following claims.

I claim:

1. A bobbin having a cross-wound mass of thread, said bobbin comprising a tubular paper core and spaced paper heads, the internal diameter of the core being substantially uniform from end to end, the wall of the core at each end portion thereof being outwardly expanded and thicker than the core wall at the midportion of the bobbin, the external peripheral surface of said thickened end portion flaring outwardly, each head having an opening for the reception of the corresponding end portion of the core, the material of the head which borders the opening converging inwardly with its free edge substantially at the. junction of the cylindrical outer surface of the core with the outer flaring surface of the thickened end portion, the material which borders the opening of the head beingunder com pression and pressing with such intimate contact against the external peripheral surface of the thickened end portion of the core as effectively to prevent relative rotationof the head and core, even when the bobbin is empty.

2. A bobbin comprising a tubular paper core having a head at each end and a thread mass cross-wound about the core and fllling the space between the heads, the internal diameter of the core being substantially uniform from end to end, the wall of the 'core being thickened at each end, the thickened portions having substantially radial end faces and outer flaring peripheral surfaces, each head having an opening for the reception of the corresponding end of the core, the material of the head which borders the opening converging inwardly toward the cylindrical outer surface of the thickened end portion of the core with the inner surface of said convergent border material in such intimate contact with the peripheral outer surface ofsaid thickened end portion of the core as to prevent relative rotation of the core and head, the inner surface of each head flaring outwardly away from its junctionswith the core; the thread massbeing under axial compression and having itsentire end surface in contact with the inner surface of .the head, the head pressing firmly against the end of the thread mass with a pressure which is greatest at the inner periphery of the mass and which decreases gradually toward the outer periphery of the mass.

3. The method of making a bobbin comprising a tubular paper core having a head at each end and a thread mass cross-wound upon the core and filling the space between the heads, which comprises as stepsproviding a paper core of a length greater than the axial thickriess of the thread mass, cross-winding the thread mass upon the central portion of the core, providing a pair of paper disks, each having a central'opening of a diameter less than the external diameter of head-forming material under hoop tension and the core, forcing each head onto the correspondcausing the bordering material to assume a coning end respectively of the core, and in so doing, tour such that it converges inwardly with its causing the material which borders the opening inner surface in intimate contact with the flarin the head to assume a substantially conical ing surface of the thickened core end and under 5 sloping contour convergent toward the outer end such compression as to prevent relative moveof the core, subjecting the assembled core and ment of the head and core, the axial compreshead to axial compression while maintaining unsion being of such intensity as to decrease the changed the internal diameter of the core, the length of the core between the ends of the thread compressive force being so applied as to expand, mass thereby thickening the core wall and im- 10 and thicken each end portion of the core and to parting radial compression to the thread mass, cause the peripheral outer surface of the thickthe axial pressure being applied to the Outer ened end portion to flare outwardly, the pressurface of the heads and being greatest adjasure exerted in thickening the end portion of the cent to the inner periphery of the mass and core being so applied as to cause the material progressively decreasing toward the outer pe- 15 which borders the opening in the head to reriphery of the thread mass. verse its direction of slope thereby placing the J. SIMPSON. 

